ABSTRACT In September 2017, the Caribbean region and southern United States was hit by four hurricanes (Irma, Harvey, Maria, and Nate), resulting in widespread and severe damage to infrastructure and ongoing disruption of social and economic systems throughout the region, including Puerto Rico. While the immediate and ongoing impact on public health has yet to be fully assessed, it may be expected that the it may also have serious consequences for a wide range of health outcomes, exacerbating pre-hurricane health disparities and placing even greater pressure on an already under-resourced health services infrastructure. Of particular concern in this application is the impact of the 2017 hurricanes on the large population of people living with HIV (PLWHIV) in Puerto Rico, including substantial proportions of vulnerable groups of women, men who have sex with men, and injection drug users. HIV testing rates among high-risk populations in PR have remained low throughout the HIV epidemic, as is engagement in HIV care, both of which contribute to increased secondary transmission. Late detection has inevitably contributed to late enrollment in care. Most PLWHIV in PR enter care with already serious compromised immune response, making them more vulnerable to HIV-related opportunistic infections and associated morbidity. Indeed PR has one of the highest HIV death rates in the US (roughly four times higher than the national average). Prior research on natural disasters of a similar in severity and scope, such as Hurricane Katrina, for example, showed that there was a significant impact on mental health (e.g., stress, trauma, etc.) and that combined external factors related to the accessibility of HIV care, resulted in significant changes in clinical HIV status. Positioned as a preliminary, R21 level initiative, we propose an exploratory study to assess whether there have been significant post-hurricane changes in clinical HIV status among PLWHIV in PR, and if so, what factors predict those changes. This application builds upon a well-established collaboration between HIV researchers in the School of Public Health at the University of Puerto Rico and Centro Latinoamericano de Enfermedades de Transmisin Sexual (CLETS), the largest HIV treatment center in PR. The ongoing CORE study within the CLETS clinic population provides a strategic opportunity to examine the impact of the 2017 hurricanes on clinical outcomes among PLWHIV in PR. We will adapt the CORE survey instruments to capture additional data related to post-hurricane behavioral risks, mental health status, and help-seeking and recover both pre-hurricane and post-hurricane clinical data for each study participant using a Targeted Chart Review process. We will examine the clinical data for three months prior to the hurricane and compare it with post-hurricane clinical data to assess whether there have been significant post-hurricane changes in HIV clinical status (CD4, viral load, OIs, etc.) among the PLWHIV, using data from the CORE survey to identify predictors of those changes. For example, post-hurricane gaps in the availability of HIV care, increased mental health distress (e.g., PTSD, anxiety, depression), and increased behavioral risk (notably in substance use) may individually and collectively have contributed to gaps in adherence. Failure to maintain viral suppression may have negative consequences for the health status of individual PLWHIV and may also amplify secondary transmission. The proposed study may inform ongoing efforts to restore critical health services for PLWHIV and inform future research in this vulnerable population.